Of the three pillars of a good golf swing, i.e., the grip, the stance, and the swing motion, the hardest to teach and maintain is a correct swing motion. Teaching professionals have many tips for monitoring the execution of a correct swing motion, such as taking the club back low and slow, extending the arms back swinging the club back over the head, keeping the wrists and arms cocked, rotation of the shoulder and the back turn aligned with the swing plane, initiating the down swing with the body not the arms, keeping the eyes on the ball and the head still, turning the hips, shifting one's weight forward toward the target, keeping a full arm extension at impact, turning the arms over to keep the clubface closed, executing a smooth follow through, keeping a proper balance and alignment at the finish of the swing, etc. While all of these are good pointers to improve a golf swing, it is difficult for the person to keep all of these swing components in mind and execute the swing correctly.
Furthermore, not all of the elements of a swing must be monitored at all times to train a person to improve their swing. Some elements, such as grip, stance, club take back, alignment, and follow through, can be taught in a limited number of sessions and need not be monitored every time a person takes a practice swing. On the other hand, some elements, such as swing tempo, hip turn, and weight shift, are so subtle or happen so quickly that they should be monitored during a person's practice swing to detect whether they were executed properly.
Many training devices and techniques have been proposed for aiding a person to execute a good swing motion. For example, U.S. Pat. Nos. 5,221,088 and 5,372,365 to McTeigue disclose measuring a person's weight shift with foot sensors, grip pressure with club handle sensors, and/or shoulder rotation with back-worn sensors to produce audible tones indicating when these factors of the swing motion are within acceptable ranges. U.S. Pat. No. 5,050,885 discloses a mechanical armature device that is attached to a person's thighs, waist, and back to maintain the desired posture, alignment, and motion of body parts during a swing. U.S. Pat. No. 3,808,707 to Fink, U.S. Pat. No. 5,040,790 to Anthes, and U.S. Pat. No. 5,082,281 to Berghofer disclose playing various types of audible cues indicative of the proper tempo and speed of the ideal swing against which the person can compare the execution of their actual swing.
However, the previous proposals have had disadvantages in that those that are attached to a person's body parts to measure or guide their motion are awkward to wear and encumber the person's swing, while those that only issue tones for the timing or tempo of a correct swing do not measure the person's actual execution of the swing. The prior devices have also provided an audible prompt for the motion of only one body part, or multiple prompts for several body parts that may be confusing for the person to listen to.
There have also been many proposals for training devices that measure the speed, angle, height, force, and/or alignment of the club during a swing. However, these devices do not provide an actual indication whether the motion of the person's body in executing the swing was correct.